Procedure and system for the transmission of information and establishment of a telecommunication connection

ABSTRACT

Procedure and system for optimizing the route of a telecommunication connection to be set up in a telecommunication system that includes a mobile switching center (MSC), a service switching point (SSP), a service control point (SCP), a gateway (GW), and a subscriber register (HLR). The service switching point is connected to the service control point and the gateway is connected to the service control point and to the subscriber register. The telecommunication connection to be set up is directed via the service switching point to the service control point. A database query is sent from the service control point, via the gateway, to the subscriber register. In response, the subscriber register returns routing information, on the basis of which an optimal route to the mobile switching center under which the B-subscriber is currently located is determined.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a reissue application of U.S. Pat. No.6,628,951 which claims priority to PCT Application PCT/FI1998/001010filed Dec. 21, 1998, and Finnish Application No. FI974590 filed Dec. 22,1997.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to telecommunication technology and, moreparticularly, the invention is directed to optimization of the route ofa telecommunication connection that is set up in a mobile communicationnetwork.

2. Description of Related Art

For a teleoperator, i.e. an owner or operator of a telecommunicationsnetwork, it is important that telecommunication connections be set up inan optimal manner. Optimization may for example be based on the lengthof the route of the connection or on the network load resulting from theconnection. Because the traffic in mobile communication networks iscontinuously increasing, it is particularly important that the load insuch networks remain as low as possible. One approach to reducing theload in a mobile communication network is to set up or establish theconnection to the mobile switching center then serving the calledsubscriber via a route that is as short as possible.

An intelligent network is formed by switching, control and functionalcomponents and a signaling network. A service switching point (SSP) ofsuch intelligent networks is a modified telephone exchange that analyzesthe traffic passing therethrough. When the SSP detects a certain numberthat meets a triggering criterion, it transmits a service request to aservice control point (SCP). The information required for servicecontrol is stored in a service data point (SDP), from which the servicecontrol point can obtain the information that it needs.

Service switching points are connected via signaling channels to servicecontrol points, which implement intelligent network services byutilizing a service database. A service control point may for exampleperform a numerical conversion from the B-number to the correspondingC-number by accessing such correspondence information from the servicedatabase.

The communication protocols used in an intelligent network are rules bywhich the components of the intelligent network talk to each other.These protocols defme the interfaces between components as well as thestructure of the messages exchanged between them. Intelligent networkcomponents communicate with each other using common channel signaling(CCS). By ITU-T definition, common channel signaling is known as CCSS No7. For communication between components, an intelligent network uses theservices of the INAP (Intelligent Network Application Part) defined byITU-T; the INAP application part is an intelligent network applicationprotocol used, for example, for communication between a service controlpoint and a service switching point. The MAP application part, on theother hand, is a portion of the signaling system of a mobilecommunication network that is used for signaling between the switchingcenters and registers of the mobile communication network.

In the GSM (Global System for Mobile communications) system, a call tobe set up or established is routed as follows. A call setup request issent from the calling subscriber's (A-subscriber's) terminal equipmentto a gateway mobile switching center (GMSC), which then sends a query tothe called subscriber's (B-subscriber's) home location register (HLR) todetermine the mobile switching center (MSC) under which theB-subscriber's terminal device is currently located. The home locationregister is implemented as a database that contains such information assubscriber data, subscriber location data, call control data,short-message services and billing data.

Next, the home location register requests the visitor location register(VLR) for a roaming number MSRN (Mobile Subscriber Roaming Number) andreturns the roaming number to the GMSC. The visitor location register isimplemented as a database in a mobile communication network whichcontains the information required for the transmission of calls abouteach mobile subscriber currently located in the area of the network. Theroaming number is a temporary identification number that is allocated toa mobile station recorded in the visitor location register and which isused by the mobile communication system for the muting of callsaddressed to that particular subscriber.

Based on the roaming number, the GMSC then routes the call originated bythe A-subscriber to the mobile switching center in whose location area(LA) the B-subscriber is currently located. The B-subscriber's mobileswitching center in turn sets up a connection with the B-subscriber'sterminal device.

The primary problem with the above-described routing procedure is thatcalls addressed to mobile stations are not automatically routed via theshortest route to the proper mobile switching center but may, instead,be routed via several switching centers. One solution that has beenapplied to eliminate this problem is to provide some service nodes (SN)and service control points with an MAP interface, thus making itpossible to implement functionality and service similar to that providedby present invention. Such solutions, however, disadvantageously theybind the service to a certain base and assume that the service controlpoint or service node is provided with an MAP interface.

In the procedure of the present invention, on the other hand, therouting of calls addressed to a terminal device is optimized by using anintelligent network service and a special gateway. By means of thatgateway, a query is sent from the intelligent network system to asubscriber register to obtain B-subscriber data and, using that data,the call to be set up is routed directly to the mobile switching centerin whose area the B-subscriber's terminal device is currently located.This arrangement and methodology additionally makes it possible toutilize other GSM network services.

OBJECTS AND SUMMARY OF THE INVENTION

It is accordingly the desideratum of the present invention to eliminate,or at least significantly reduce, the drawbacks and deficiencies of theprior art, as for example described hereinabove.

It is a particular object of the invention is to provide a new type ofprocedure and system for routing a new call being set up directly to themobile switching center under which the B-subscriber is currentlylocated.

The procedure of the invention is thus utilized to optimize the route ofa telecommunication connection to be set up, as for example andpreferably in a mobile communication system.

The telecommunication system of the present invention comprises a mobileswitching center, a service switching point, a service control point, agateway, and a subscriber register. The service switching point isconnected to the service control point, and the subscriber register andservice control point are connected to the gateway. The gateway furthercomprises means for handling a database query, a signaling query, aresponse to a database query, and a response to a signaling query.

In the method of the present invention, a telecommunication connectionto be set up is directed via the service switching point to the servicecontrol point. From the service control point, a database query isperformed, which is directed to the gateway. The database query isconverted in the gateway into a signaling query which is sent to thesubscriber register. Using the data in the subscriber register, aresponse to the signaling query is defined and returned to the gateway,at which the response to the signaling query is converted to a responseto the database query, on the basis of which the service control pointdetermines an optimal route to the appropriate mobile switching center.

In preferred embodiments of the invention, the response to the signalingquery contains routing information which is used to optimize the routeof the telecommunication connection to the mobile switching center. Aconnection to the mobile switching center, and further by way of exampleto the B-subscriber's terminal device, is then set up. The routinginformation may for example be a roaming number, such preferably as theMobile Subscriber to Roaming Number MSRN.

In the same or other preferred embodiments of the invention, the gatewaymay be an MAP-INAP gateway, which comprises means for controlling theinterface between the service control point and the database and meansfor controlling the interface between the gateway mobile servicesswitching center and the subscriber register. The signaling query ispreferably an MAP (Mobile Application Part) query and the database queryan SDP (Service Data Point) query. As a consequence of this arrangement,the service control point of the intelligent network is able to use thesubscriber data of the GSM network.

In these or other preferred embodiments of the invention, the subscriberregister may be the home location register of the GSM system.

The present invention thus allows optimal routing to the mobileswitching center under which the B-subscriber is then or currentlylocated. If, according to the data in the visitor location register, thesubscriber cannot be reached, then corresponding information isobtained. If the subscriber has transferred his or her calls to anothernumber using the CFU (Call Forwarding Unconditional) supplementaryservice, this too will be known so that the call can be properly routedto the specified forward number.

As will be further appreciated, the inventive solution advantageouslydoes not require any changes in the elements of the mobile communicationnetwork or in the intelligent network because the invention implementsthe enhanced service through the use of a separate MAP-INAP base.

Other objects and features of the present invention will become apparentfrom the following detailed description considered in conjunction withthe accompanying drawings. It is to be understood, however, that thedrawings are designed solely for purposes of illustration and not as adefinition of the limits of the invention, for which reference should bemade to the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, wherein like reference numerals denote similar elementsand method steps throughout the several figures:

FIG. 1 is a block diagram of a system in accordance with the presentinvention;

FIG. 2 diagrammatically depicts an example of signaling in a preferredembodiment of the inventive procedure in which the home locationregister provides, in response to a database query, a roaming number ofthe called or B-subscriber;

FIG. 3 diagrammatically depicts an example of signaling in a preferredembodiment of the procedure of the invention in a situation in which theB-subscriber has forwarded his or her calls to a C-number; and

FIG. 4 diagrammatically depicts an example of signaling in a preferredembodiment of the inventive procedure in an error situation.

The signaling diagram in FIG. 4 comprises a service control point (SCP),an MAP-INAP gateway (GW) and a home location register (HLR).

DETAILED DESCRIPTION OF THE CURRENTLY PREFERRED EMBODIMENTS

The system configured in accordance with the present invention andillustrated in FIG. 1 comprises a mobile switching center MSC and aservice switching point SSP which is connected to a service controlpoint SCP. In addition, the service control point SCP is connected to agateway GW which, in turn, is also connected to a subscriber registerHLR.

In the signaling diagram of FIG. 2, the system includes a servicecontrol point SCP, an MAP-INAP gateway GW, a home location register HLR,and a visitor location register (VLR).

In the signaling diagram of FIG. 3, the system includes a servicecontrol point SCP, an MAP-INAP gateway 6W, and a home location registerHLR. With initial reference to FIG. 1, an effort to establish acommunication connection starts with a call setup request that is sentfrom the terminal device (not shown) of a calling or A-subscriber to thegateway mobile services switching center MSC. The gateway MSC detectsthe incoming call and further directs it to the service switching pointSSP. From switching point SSP, the call is directed to the servicecontrol point SCP, which performs a database query to obtain routinginformation. In accordance with the procedure of the present invention,instead of directing the database query to the service data point, thequery is directed to an MAP-INAP gateway GW, at which a conversion froma database query to a signaling query is performed. The MAP-INAP gatewaymay be readily implemented, as for example by using a separate servicenode provided with the required applications to implementation theappropriate interfaces or by installing the application in an existingintelligent network component, such as the service control point SCP.

The routing query is then sent from the gateway GW to the called orB-subscriber's home location register, at which a response to thesignaling query is defined utilizing the data in the home locationregister HLR. The signaling query response consists of routinginformation, preferably a roaming number identified with theB-subscriber. The home location register returns the routing informationto the gateway GW, which then performs a conversion so from thesignaling query response to a database query response. The routinginformation is thus converted into a form understood by the servicecontrol point SCP. Based on the database query response received, theservice control point next causes the service switching point to routethe call directly to the mobile switching center under which heB-subscriber's terminal device is currently located.

FIG. 2 presents an example of the signaling procedure of the inventionin a situation in which the home location register provides, in responseto a database query, a roaming number of the called or B-subscriber. Theservice control point SCP sends a database query (DB-query) to obtainrouting information MSRN. The database query is directed to an MAP-INAPgateway GW, at which a conversion from the database query to a signalingquery is performed. The signaling query (Send.Routing.Inf) is then sentfrom the gateway to the B-subscriber's home location register HLR, wherea response to the signaling query is defined using the data in the homelocation register. In currently-used techniques, the subscriber locationdata is not always automatically updated from the visitor locationregister to the home location register. In this case, the home locationregister HLR must first get routing information (Provide.MSRN) from thevisitor location register VLR. The home location register then returnsits response to the signaling query (HLR-response) to the gateway, whichperforms a conversation from the signaling query response (HLR-response)to a database query response (DB-response). The signaling query response(HLR-response) consists of routing information, preferably a roamingnumber.

FIG. 3 presents an example of the signaling procedure of the presentinvention in a situation in which the B-subscriber has forwarded his orher to another or C-number. From the service control point SCP, adatabase query (DB-query) is sent to obtain routing information MSRN.The database query is directed from service control point SCP to theMAP-INAP gateway GW, at which a conversion from the database query to asignaling query (Send.Routing.Inf) is preformed. The signaling query isthen sent from the gateway to the home location register HLR of theB-subscriber where, based on the data in the home location register, aresponse to the signaling query in defined. The home location registerHLR returns its response to the signaling query (Fwd.To.Number) to thegateway, which performs a conversion from the signaling query responseto a database query response (DB-response). In this example, therefore,the response (Fwd.To.Number) to the signaling query is a C-number.

FIG. 4 illustrates an example of the inventive signaling procedure in asituation in which the B-subscriber cannot be reached or there is amalfunction in the telecommunication system. A database query (DB-query)is sent from the service control point SCP to obtain routinginformation. The database query is directed to the MAP-INAP gateway GW,at which a conversion from the database query to a signaling query isperformed. Next, the signaling query (Send.Routing.Inf) is sent from thegateway to the home location register HLR of the B-subscriber and, basedon the information in the home location register, a response(Routing.Inf.Error) to the signaling query is defined. If the subscriberterminal has been shut off or the subscriber is outside of the receivingarea, then the response (Routing.Inf.Error) to the signaling querycontains data indicating that the subscriber cannot be reached. If thereis a malfunction in the system, then corresponding information can alsobe given to the service control point in the response(Routing.Inf.Error) to the signaling query. The home location registerthen returns the signaling query response to the gateway, which performsa conversion from the signaling query response to a database queryresponse (DB-error).

The invention herein described and disclosed is based in part oncommonly-owned Finnish Patent Application No. 982168 entitled “Procedureand System for the Transmission of Information and Setting Up of aTelecommunication Connection”, the entire disclosure of which is herebyexpressly incorporated by reference herein.

While there have shown and described and pointed out fundamental novelfeatures of the invention as applied to preferred embodiments thereof,it will be understood that various omissions and substitutions andchanges in the form and details of the methods and procedures describedand devices illustrated, and in their operation, may be made by thoseskilled in the art without departing from the spirit of the invention.For example, it is expressly intended that all combinations of thoseelements and/or method steps which perform substantially the samefunction in substantially the same way to achieve the same results arewithin the scope of the invention. Moreover, it should be recognizedthat structures and/or elements and/or method steps shown and/ordescribed in connection with any disclosed form or embodiment of theinvention may be incorporated in any other disclosed or described orsuggested form or embodiment as a general matter of design choice. It isthe intention, therefore, to be limited only as indicated by the scopeof the claims appended hereto.

1. A procedure for route optimization of a telecommunication connection to be set up between a calling subscriber and a called subscriber in a telecommunication system that includes a mobile switching center, a service control point, a service switching point connected to the service control point, a subscriber register, and a gateway connected to the service control point and to the subscriber register, comprising the steps of: directing the telecommunication connection to be set up to the service control point via the service switching point; performing a database query directed from the service control point and addressed to the subscriber register; and determining an optimal route to the mobile switching center currently serving the called subscriber based on a response from the subscriber register to the database query; wherein said performing step comprises: directing the database query from the service control point to the subscriber register via the gateway; converting, in the gateway, the database query from the service control point into a signaling query; sending the converted signaling query from the gateway to the subscriber register; defining, at the subscriber register, a signaling query response to the converted signaling query; sending the signaling query response from the subscriber register to the gateway; converting, in the gateway, the signaling query response to a responsive database query; and returning the responsive database query from the gateway to the service control point.
 2. The procedure of claim 1, wherein said determining step comprises: generating optimized routing information for the telecommunication connection between the calling subscriber and the called subscriber using the responsive database query received by the service control point; and setting up the telecommunication connection to the mobile switching center currently serving the called subscriber using the generated routing information to thereby establish an optimized route between the calling subscriber and the called subscriber.
 3. The procedure of claim 1, wherein the response from the subscriber register to the database query comprises routing information.
 4. The procedure of claim 1, wherein the response from the subscriber register to the database query comprises routing information comprising a roaming number of the called subscriber.
 5. The procedure of claim 4, wherein the roaming number comprises a Mobile Subscriber Roaming Number.
 6. The procedure of claim 1, wherein the gateway comprises an MAP-INAP gateway comprising a database interface and a subscriber register interface.
 7. The procedure of claim 1, wherein the signaling query comprises an MAP query.
 8. The procedure of claim 1, wherein the database query comprises a Service Data Point query.
 9. The procedure of claim 1, wherein the subscriber register comprises a home location register.
 10. In a system for optimizing a route of a telecommunication connection to be set up between a calling subscriber and a called subscriber iD a telecommunication system that includes a mobile switching center, a service control point, a service switching point connected to the service control point, and a subscriber register, and wherein the telecommunication connection to be set up is directed to the service control point via the service switching point, the improvement comprising: a gateway connected to the service control point and to the subscriber register, said gateway comprising: means for handling a database query, a signaling query, a database query response and a signaling query response; means for receiving a database query from said service control point; means for changing said database query to said signaling query; means for sending said signaling query to said subscriber register; means for receiving a signaling query response from said subscriber register; means for changing said signaling query response to said database query response; and means for sending said data query response to said service control point.
 11. A method comprising: receiving, at a gateway, a database query from a service control point; converting, at the gateway, the database query received from the service control point into a signaling query; sending, from the gateway, the signaling query to a subscriber register; receiving, at the gateway, a signaling query response from the subscriber register comprising routing information in a first format; converting, at the gateway, the signaling query response comprising routing information in the first format into a database query response comprising the routing information in a second format; and sending, from the gateway, the database query response comprising the routing information in the second format to the service control point, wherein, in response to receiving the database query response, the service control point determines an optimal route to a mobile switching center serving the called terminal based on the database query response comprising routing information in the second format, and directs a service switching point to conduct routing for connection setup to the mobile switching center serving the called terminal.
 12. The method of claim 11, wherein the service control point generates the database query in response to an incoming call received from the service switching point.
 13. The method of claim 11, wherein the gateway is a mobile application part-intellectual network application part (MAP-INAP) gateway.
 14. The method of claim 11, wherein the gateway is integrated with the service control point.
 15. The method of claim 11, wherein the gateway is an independent service node.
 16. The method of claim 11, wherein the subscriber register is a home location register.
 17. The method of claim 11, wherein the routing information is a roaming number associated with the called terminal.
 18. The method of claim 11, wherein the signaling query response is based on information provided by a visitor location register.
 19. The method of claim 11, wherein the signaling query response includes a call forwarding number.
 20. The method of claim 11, wherein the signaling query response includes information indicating that the called terminal cannot be reached.
 21. The method of claim 11, wherein the gateway is part of a telecommunication system including the mobile switching center, the service control point, the service switching point communicatively connected to the service control point, and the subscriber register.
 22. The method of claim 21, wherein the gateway is configured to handle the database query, the signaling query, the database query response, and the signaling query response.
 23. A system comprising: a service control point; a service switching point; a subscriber register; and a gateway configured to: receive a database query from the service control point; convert the database query received from the service control point into a signaling query; send the signaling query to the subscriber register; receive, from the subscriber register, a response to the signaling query, the response comprising routing information in a first format; convert the received response comprising routing information in the first format into a database query response comprising the routing information in a second format; and send the database query response comprising the routing information in the second format to the service control point, wherein, in response to receiving the database query response, the service control point is configured to determine an optimal route to a mobile switching center serving the called terminal based on the database query response comprising the routing information in the second format, and direct the service switching point to conduct routing for connection setup to the mobile switching center serving the called terminal.
 24. The system of claim 23, wherein the service control point is configured to generate the database query in response to an incoming call received from the service switching point.
 25. The system of claim 23, wherein the gateway is a mobile application part-intellectual network application part (MAP-INAP) gateway.
 26. The system of claim 23, wherein the gateway is integrated with the service control point.
 27. The system of claim 23, wherein the gateway is an independent service node.
 28. The system of claim 23, wherein the subscriber register is a home location register.
 29. The system of claim 23, wherein the routing information is a roaming number associated with the called terminal.
 30. The system of claim 23, wherein the received response to the signaling query is based on information provided by a visitor location register.
 31. The system of claim 23, wherein the received response to the signaling query includes a call forwarding number.
 32. The system of claim 23, wherein the received response to the signaling query includes information indicating that the called terminal cannot be reached.
 33. The system of claim 23, wherein the system further comprises the mobile switching center, and wherein the service switching point is communicatively connected to the service control point.
 34. The system of claim 33, wherein the gateway is configured to handle the database query, the database query response, the signaling query, and the response to the signaling query. 